You will be able to set many automatic emails which will send to your customers after specified action. For example when customers often leave their shopping carts without purchase, you can make e-mails which will be send to all abandoned cart.
Reminder name - Name of your reminder
Active - Is reminder active or not?
Start/End Date - When reminder should be active.
Activity date for rule - Activity date. Reminder will count from or to this date
Display Order - Display order of reminder
Allow renew - Choose when reminder should run again
Reminder Rule -
Adding conditions is the same as in Customer Actions, described here. More interesting is adding reminders levels.
Level - You can specify which level it will be, 1 - 1st send mail, 2 - 2nd, etc
Level name - Name of level
Send after days - Send this email after N days after previous level
Send after hours - Send this email after N hours after previous level
Email Accounts - Which email account will send this email
BCC - Blind Carbon Copy
Subject - Subject of mail
Allowed Tokens - Token which you can use in mail
Body - Body of mail